Copper-zinc alloys



Patented Apr. 1, 1941 COPPER-ZINC ALLOYS Wolf Johannes Miiller and Moritz Niessner,

Vienna, Germany, assignors, by mesne assignments, to Aktiengesellschaft Dynamit Nobel, Pressburg, Slovakia, a company No Drawing. Application June 24, 1938, Serial No. 215,588. In Austria July 21, 1934 2 Claims. (Cl. 75--155) It is known that gamma-brass, that is to say copper-zinc alloys with a copper content of about 31-40%, i. e., alloys which are characterized by a low copper content, are more resistant to corrosion than the brass alloys of the alpha and alpha and beta region with for instance 68-72 per cent and more of copper, i. e., a higher copper content. The technical employment of gamma-alloys poor in copper is however impossible, since these alloys are extremely hard and brittle and are consequently not machinable.

From such alloys, as is described in our prior Patents No. 2,006,598 and 2,006,599 it has been disclosed that it is possible, by the addition of a iew percent of a metal soluble in gamma-brass or alloyable therewith, such as nickel or, with more advantage cobalt, preferably by a simultaneous addition of nickel and cobalt, to obtain alloys, which possess the good resistance to corrosion of gamma-alloys poor in copper, but are also capable of being worked up, that is to say can be treated with machine tools and can also be rolled hot. Such alloys with an addition of approxi- -mately 3-12% of cobalt, nickel or the like individually or in mixture, that is to say for instance pure copper-zinc alloys with a minimum content of nickel of approximately 7-8% or of cobalt of approximately -6% have extremely good technical properties, and when cobalt and nickel are used simultaneously it is possible with a much smaller cobalt content to obtain the same efiects as with the use of cobalt alone. quently alloys that are deficient in copper, even those most deficient, can be made utilisable for industrial purposes or as constructional material for theproduction of articles, if the copper-zinc alloys arealloyed with cobalt, nickel or the like individually or in mixture.

The present invention is based on the ascertained fact that such copper-zinc alloys, containing between 30 and 45% of copper and between 3 and 12% of cobalt and/or nickel, can have their properties substantially improved when containing also between 4 and 15% of manganese and at least a small but efiective amount of one of the metals of the following group:

Per cent I1'0n..;. Up to 1.8 Aluminium Up to 1.5 Silver Up to 2.0 Chromium Up to 3.0 Tin' Up to 2.0 Lead Up to 0.3 Selenium Up to 0.6 Tellurium Up to 0.6

but in no greater amounts than are soluble in the Consesolid solution and the zinc constituting substantially the remainder.

It has been ascertained that such alloys are suitable for cold working, including cold rolling,

proportional improvement in the cold working properties.

By the addition of the metals of the group: iron, aluminium, silver, chromium, tin, lead, selenium and tellurium the workability in the cold, the colour and other-properties of the alloys are favourably influenced as compared with such alloys containing only copper, zinc, nickel and/or cobalt and manganese as are subject of our co-pending application Ser. No. 148,506 filed June 16, 1937, from which the present applica tion is divided out.

" Thus an enhanced workability in the cold can be imparted to the alloys-of the invention, by

the addition of suitable amounts of one or more of the elements iron, lead, tin, selenium and tellurium within the limits hereinbefore set forth while their corrosion resistance can be enhanced by the addition of one or more of the metals aluminium, chromium and tin within the limits hereinbefore set forth;

It is easy to ascertain empirically, the amount of each element that will produce the most favorable efiect.

A suitable alloy in accordance with the invention is one containing between and of copper, between 3 and 12% of cobalt and/or nickel, between 4 and 15% of manganese and between 0.5 and 1.5% of iron.

The addition of up to 0.3% of phosphorus to the hereindescribed alloys is advantageous since it very considerably improves the fineness of structure of the alloys.

By means of the additions according to the invention the range of the solid solution can also beincreased, to some extent, beyond that of the binary alloy, and alloys with a somewhat higher copper content which however must be substantially less than 45%,. which come within the beta gamma range in the binary alloy, can also be converted into a state corresponding to gamma brass and rendered suitable for applications, such as cold rolling or drawing, from which they are otherwise excluded on account of their copper content.

Q The following is a typical example of an alloy according to the invention:

What we claim is:

1. A corrosion-resistant copper-zinc alloy which is workable in the cold state, comprising copper in the amount of 30 to 45%, at least one metal of the group cobalt and nickel in an amount of 3 to 12%, manganese in an amount of 4 to 15%, iron from 0.5 to 1.5% and an. additional element capable of improving the workability of the alloy in the cold state selected from the group consisting of lead, phosphorus, selenium and tellurium, said additional element be-' ing present in no greater amount than is soluble in the solid solution and which could substantlally impair the corrosion resistance of the al loy, the zinc constituting substantially all the remainder of the alloy.

2. A corrosion-resistant copper-zinc alloy.

which is workable in the cold state, comprising copper in'the amount of 30 to 45%, at least one metal of the group cobalt and nickel in an. amount of 3 to 12%, manganese in an amount of 4 to 15%, iron 0.5 to 1.5% and a small but effective amount of an additional element capable of improving the workability of the alloy in the cold state selected from the following group, in the percentages indicated:

Per cent Lead Up to 0.3 Phospherus Up to 0.3 Selenium Up to 0.6 Tellurium Up to 0.6

the zinc constituting substantially all the re- 20 mainder of the alloy.

WOLF JOHANNES MUHER. MORI'I'Z NIESSNER. 

